ST TDA7296 User Manual

TDA7296

Fi

70V - 60W DMOS AUDIO AMPLIFIER WITH MUTE/ST-BY

1 FEATURES

■ MULTIPOWER BCD TECHNOLOGY

■ VERY HIGH OPERATING VOLTAGE RANGE

(±35V)

■ DMOS POWER STAGE

■ HIGH OUTPUT POWER (UP TO 60W MUSIC

POWER)

■ MUTING/STAND-BY FUNCTIONS

■ NO SWITCH ON/OFF NOISE

■ NO BOUCHEROT CELLS

■ VERY LOW DISTORTION

■ VERY LOW NOISE

■ SHORT CIRCUIT PROTECTION

■ THERMAL SHUTDOWN

2 DESCRIPTION

The TDA7296 is a monolithic integrated circuit in
Multiwatt15 package, intended for use as audio
class AB amplifier in Hi-Fi field applications (Home
Stereo, self powered loudspeakers, Topclass TV).

Figure 2. Typical Application and Test Circuit

gure 1. Package

Multiwatt15V

Multiwatt15H

(Short Leads)

Table 1. Order Codes

Part Number Package

TDA7296 Multiwatt15V

TDA7296HS Multiwatt15H (Short Leads)

Thanks to the wide voltage range and to the high
out current capability it is able to supply the high­est power into both 4Ω and 8Ω loads even in pres­ence of poor supply regulation, with high Supply
Voltage Rejection.

The built in muting function with turn on delay sim­plifies the remote operation avoiding switching on­off noises.

VM

VSTBY

February 2005

+VsC7 100nF C6 1000µF

R3 22K

C2

R2

22µF

680Ω

C1 470nF

R1 22K

R5 10K

R4 22K

C3 10µF C4 10µF

Note: The Boucherot cell R6, C10, normally not necessary for a stable operation it could
be needed in presence of particular load impedances at V

IN- 2

IN+

IN+MUTE

MUTE

STBY

3

4

10

MUTE

9

STBY

1

STBY-GND

713

-

+

THERMAL

SHUTDOWN

-Vs -PWVs

C9 100nF C8 1000µF

<±25V.

S

+PWVs+Vs

PROTECTION

158

-Vs

S/C

14

OUT

C5

22µF

6

BOOT­STRAP

D93AU011

R6

2.7Ω

C10

100nF

Rev. 10

1/15

TDA7296

Figure 3. Pin Connection

Table 2. Absolute Maximum Ratings

Symbol Parameter Value Unit

V

I

O

P

tot

T

op

T

stg

Supply Voltage (No Signal) ±35 V

S

Output Peak Current 5 A

Power Dissipation T

= 70°C 50 W

case

Operating Ambient Temperature Range 0 to 70 °C

, TjStorage and Junction Temperature 150 °C

Table 3. Thermal Data

Symbol Parameter Typ. Max Unit

R

th j-case

Thermal Resistance Junction-case 1 1.5 °C/W

Figure 4. Block Diagram

2/15

TDA7296

Table 4. Electrical Characteristcs (Refer to the Test Circuit VS = ±24V, RL = 8Ω, GV = 30dB; Rg = 50Ω;

= 25°C, f = 1 kHz; unless otherwise specified).

T

amb

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

V

I

P

SR Slew Rate 7 10 V/µs

G

G

f

L ,fH

SVR Supply Voltage Rejection f = 100Hz; V

STAND-BY FUNCTION (Ref: -Vs or GND)

V

ST on

V

ST off

AT T

I

q st-by

MUTE FUNCTION (Ref: -Vs ro GND)

V

V

AT T

Note (*):
MUSIC POWER is the maximal power which the amplifier is capable of producing across the rated load resistance (regardless of non linearity)
1 sec after the application of a sinusoidal input signal of frequency 1KHz.

Supply Range ±10 ±35 V

S

I

Quiescent Current 20 30 65 mA

q

I

Input Bias Current 500 nA

b

Input Offset Voltage -10 10 mV

OS

Input Offset Current -100 100 nA

OS

RMS Continuous Output

O

Power

Music Power (RMS)
∆t = 1s (*)

d Total Harmonic Distortion (**) P

d = 05%

= ± 24V, RL = 8Ω;

V

S

V

= ± 21V, RL = 6Ω;

S

VS = ± 18V, RL = 4Ω;

d = 10%

= ± 29V, RL = 8Ω;

V

S

V

= ± 24V, RL = 6Ω;

S

V

= ± 22V, RL = 4Ω;

S

= 5W; f = 1kHz

O

27
27
27

30
30
30

60
60
60

0.005

PO = 0.1 to 20W; f = 20Hz to 20kHz

V

= ± 18V, RL = 4Ω;

S

PO = 5W; f = 1kHz
P

= 0.1 to 20W; f = 20Hz to 20kHz

O

Open Loop Voltage Gain 80 dB

V

Closed Loop Voltage Gain (1) 24 30 40 dB

V

e

Total Input Noise A = curve 1 µV

N

0.01

f = 20Hz to 20kHz 2 5 µV

frequency response (-3dB) PO =1W 20Hz to 20kHz

R

Input Resistance 100 kΩ

i

= 0.5Vrms 60 75 dB

ripple

T

Thermal Shutdown 145 °C

S

Stand-by on Threshold 1.5 V

Stand-by off Threshold 3.5 V

Stand-by Attenuation 70 90 dB

st-by

Quiescent Current @ Stand-by 1 3 mA

Mute on Threshold 1.5 V

Mon

Mute off Threshold 3.5 V

Moff

Mute AttenuatIon 60 80 dB

mute

0.1

0.1

W
W
W

W
W
W

%

%
%

Note (**): Tested with optimized Application Board (see fig.5)

3/15

TDA7296

Figure 5. P.C.B. and Components Layout of the Circuit of figure 2.

Note:
The Stand-by and Mute functions can be referred either to GND or -VS.
On the P.C.B. is possible to set both the configuration through the jumper J1.

4/15

TDA7296

3 APPLICATION SUGGESTIONS

(see Test and Application Circuits of the Fig. 2)

The recommended values of the external components are those shown on the application circuit of Figure

2. Different values can be used; the following table can help the designer.

COMPONENTS

R1 (*) 22k Input Resistance Increase Input

R2 680Ω Closed Loop Gain

R3 (*) 22k Increase of Gain Decrease of Gain

R4 22k St-by Time Constant Larger St-by

R5 10k Mute Time Constant Larger Mute

C1 0.47µF Input DC Decoupling Higher Low Frequency

C2 22µF Feedback DC

C3 10µF Mute Time Constant Larger Mute

C4 10µF St-by Time Constant Larger St-by

C5 22µF Bootstrapping Signal Degradation at

SUGGESTED

VALUE

PURPOSE

Set to 30db (**)

Decoupling

LARGER THAN

SUGGESTED

Impedance

Decrease of Gain Increase of Gain

ON/OFF Time

ON/OFF Time

ON/OFF Time

ON/OFF Time

SMALLER THAN

SUGGESTED

Decrease Input

Impedance

Smaller St-by ON/OFF

Time; Pop Noise

Smaller Mute

ON/OFF Time

Higher Low Frequency

Smaller Mute ON/OFF

Smaller St-by ON/OFF

Time; Pop Noise

Low Frequency

Cutoff

Cutoff

Time

C6, C8 1000µF Supply Voltage Bypass Danger of Oscillation

C7, C9 0.1µF Supply Voltage Bypass Danger of Oscillation

(*) R1 = R3 for pop optimization
(**) Closed Loop Gain has to be ≥ 24dB

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TDA7296

4 TYPICAL CHARACTERISTICS

(Application Circuit of fig 2 unless otherwise specified)

Figure 6. : Output Power vs. Supply Voltage.

Figure 9. Distortion vs. Output Power

Figure 7. Distortion vs. Output Power

Figure 8. Output Power vs. Supply Voltage

Figure 10. Distortion vs. Frequency

Figure 11. Distortion vs. Frequency

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TDA7296

Figure 12. Quiescent Current vs. Supply

Voltage

Figure 13. Supply Voltage Rejection vs.

Frequency

Figure 15. St-by Attenuation vs. V

pin9

Figure 16. Power Dissipation vs. Output Power

Figure 14. Mute Attenuation vs. V

pin10

Figure 17. Power Dissipation vs. Output Power

7/15

TDA7296

5 INTRODUCTION

In consumer electronics, an increasing demand has arisen for very high power monolithic audio amplifiers
able to match, with a low cost the performance obtained from the best discrete designs.

The task of realizing this linear integrated circuit in conventional bipolar technology is made extremely dif­ficult by the occurence of 2nd breakdown phenomenon. It limits the safe operating area (SOA) of the pow­er devices, and as a consequence, the maximum attainable output power, especially in presence of highly
reactive loads. Moreover, full exploitation of the SOA translates into a substantial increase in circuit and
layout complexity due to the need for sophisticated protection circuits.

To overcome these substantial drawbacks, the use of power MOS devices, which are immune from sec­ondary breakdown is highly desirable. The device described has therefore been developed in a mixed bi­polar-MOS high voltage technology called BCD 80.

5.1 Output Stage

The main design task one is confronted with while developing an integrated circuit as a power operational
amplifier, independently of the technology used, is that of realising the output stage. The solution shown
as a principle schematic by Fig 18 represents the DMOS unity-gain output buffer of the TDA7296.

This large-signal, high-power buffer must be capable of handling extremely high current and voltage levels
while maintaining acceptably low harmonic distortion and good behaviour over frequency response; more­over, an accurate control of quiescent current is required.

A local linearizing feedback, provided by differential amplifier A, is used to fullfil the above requirements,
allowing a simple and effective quiescent current setting. Proper biasing of the power output transistors
alone is however not enough to guarantee the absence of crossover distortion. While a linearization of the
DC transfer characteristic of the stage is obtained, the dynamic behaviour of the system must be taken
into account.

A significant aid in keeping the distortion contributed by the final stage as low as possible is provided by
the compensation scheme, which exploits the direct connection of the Miller capacitor at the amplifier’s
output to introduce a local AC feedback path enclosing the output stage itself.

5.2 Protections

In designing a power IC, particular attention must be reserved to the circuits devoted to protection of the
device from short circuit or overload conditions.

Due to the absence of the 2nd breakdown phenomenon, the SOA of the power DMOS transistors is de­limited only by a maximum dissipation curve dependent on the duration of the applied stimulus.

In order to fully exploit the capabilities of the power transistors, the protection scheme implemented in this
device combines a conventional SOA protection circuit with a novel local temperature sensing technique
which " dynamically" controls the maximum dissipation.

Figure 18. Principle Schematic of a DMOS Unity-gain Buffer.

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Figure 19. Turn ON/OFF Suggested Sequence

+Vs

(V)

+35

-35

-Vs

V

IN

(mV)

V

ST-BY

PIN #9

(V)

5V

TDA7296

V

MUTE

PIN #10

(V)

I

P

(mA)

V

OUT
(V)

5V

OFF

ST-BY

PLAY

MUTE MUTE

ST-BY OFF

D93AU013

In addition to the overload protection described above, the device features a thermal shutdown circuit
which initially puts the device into a muting state (@ Tj = 145°C) and then into stand-by (@ Tj = 150°C).

Full protection against electrostatic discharges on every pin is included.

5.3 Other Features

The device is provided with both stand-by and mute functions, independently driven by two CMOS logic
compatible input pins.

The circuits dedicated to the switching on and off of the amplifier have been carefully optimized to avoid
any kind of uncontrolled audible transient at the output.

The sequence that we recommend during the ON/OFF transients is shown by Figure 19.

The application of figure 20 shows the possibility of using only one command for both st-by and mute func­tions. On both the pins, the maximum applicable range corresponds to the operating supply voltage.

9/15

TDA7296

Figure 20. Single Signal ST-BY/MUTE Control Circuit

MUTE/

20K

ST-BY

10K 30K

MUTE STBY

1N4148

10µF10µF

D93AU014

6 BRIDGE APPLICATION

Another application suggestion is the BRIDGE configuration, where two TDA7296 are used, as shown by
the schematic diagram.

In this application, the value of the load must not be lower than 8 Ohm for dissipation and current capability
reasons. A suitable field of application includes HI-FI/TV subwoofers realizations. The main advantages
offered by this solution are:

– High power performances with limited supply voltage level.

– Considerably high output power even with high load values (i.e. 16 Ohm).

The characteristics shown by figures 23 and 24, measured with loads respectively 8 Ohm and 16 Ohm.
With R
±24V the maximum Pout is 60W.

Figure 21. Bridge Application Circuit

= 8 Ohm, Vs = ±18V the maximum output power obtainable is 60W, while with Rl=16 Ohm, Vs =

l

+Vs

Vi

ST-BY/MUTE

10K 30K

20K

22µF

1N4148

0.56µF 22K

2200µF0.22µF

3

22K0.56µF

1

4

10

9

9

10

22µF

3

1

4

137

+

-

15 8

+

-

137

815

6

14

2

2200µF

6

14

2

22µF

22K

680

22K

-Vs

0.22µF

22µF

22K

680

D93AU015A

10/15

TDA7296

Figure 22. Frequency Response of the Bridge

Application

Figure 23. Distortion vs. Output Power

Figure 24. Distortion vs. Output Power

11/15

TDA7296

Figure 25. Multiwatt15V Mechanical Data & Package Dimensions

DIM.

A5 0.197

B 2.65 0.104

C 1.6 0.063

D 1 0.039

E 0.49 0.55 0.019 0.022

F 0.66 0.75 0.026 0.030

G 1.02 1.27 1.52 0.040 0.050 0.060

G1 17.53 17.78 18.03 0.690 0.700 0.710

H1 19.6 0.772

H2 20.2 0.795

L 21.9 22.2 22.5 0.862 0.874 0.886

L1 21.7 22.1 22.5 0.854 0.87 0.886

L2 17.65 18.1 0.695 0.713

L3 17.25 17.5 17.75 0.679 0.689 0.699

L4 10.3 10.7 10.9 0.406 0.421 0.429

L7 2.65 2.9 0.104 0.114

M 4.25 4.55 4.85 0.167 0.179 0.191

M1 4.73 5.08 5.43 0.186 0.200 0.214

S 1.9 2.6 0.075 0.102

S1 1.9 2.6 0.075 0.102

Dia1 3.65 3.85 0.144 0.152

mm inch

MIN. TYP. MAX. MIN. TYP. MAX.

OUTLINE AND

MECHANICAL DATA

Multiwatt15 (Vertical)

12/15

0016036 J

Figure 26. Multiwatt15 Horizontal (Short leads) Mechanical Data & Package Dimensions

TDA7296

DIM.

mm inch

MIN. TYP. MAX. MIN. TYP. MAX.

A50.197

B 2.65 0.104

C1.60.063

E 0.49 0.55 0.019 0.022

F 0.66 0.75 0.026 0.030

G 1.02 1.27 1.52 0.040 0.050 0.060

G1 17.53 17.78 18.03 0.690 0.700 0.709

H1 19.6 20.2 0.772 0.795

H2 19.6 20.2 0.772 0.795

L1 17.80 18.00 18.20 0.701 0.709 0.717

L2 2.54 0.100

L3 17.25 17.5 17.75 0.679 0.689 0.699

L4 10.3 10.7 10.9 0.406 0.421 0.429

L5 2.70 3.00 3.30 0.106 0.118 0.130

L7 2.65 2.9 0.104 0.114

R 1.5 0.059

S 1.9 2.6 0.075 0.102

S1 1.9 2.6 0.075 0.102

Multiwatt15 H (Short leads)

Dia1 3.65 3.85 0.144 0.152

OUTLINE AND

MECHANICAL DATA

H2

V

R

R

B

L5

F

G1

G

V

E

N

V V

C

L1L2

L3

L4

R1 P

L7

Diam 1

S1

V

A

H2

H1

S

MW15HME

0067558 E

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TDA7296

Table 5. Revision History

Date Revision Description of Changes

January 2004 8 First Issue in EDOCS DMS

September 2004 9 Added Package Multiwatt15 Horizontal (Short leads)

February 2005 10 Corrected mistyping error in Table 2.

14/15

TDA7296

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by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject
to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not
authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.

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